Apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value

ABSTRACT

An apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value comprises a housing accommodating a hollow shaft journalled in bearings and supporting a rotary atomizer at the end there of facing the combustion chamber, and an annular air duct for supplying air for combustion, which is arranged around the rotary atomizer. The hollow shaft accommodates a pipe for feeding the industrial wastes being burned to the inner surface of the rotary atomizer, as well as a pilot burner which is adapted to form an independently controlled flame along the axis of the spatter cone of the wastes being burned.

United States Patent Vat-ms et a1.

APPARATUS FOR ATOMIZATION AND COMBUSTION 01F FLUID INDUSTRIAL WASTES HAVING LOW AND VARIABLE CALORIFIC VALUE I Inventors: Georgy Alfonsovich Vorms,

prospekt Oktyabrya 133, kv. 35; Petr lvanovich Kuznetsov, ulitsa Rossiiskaya, 56 v", kv. 51; Vladislav Borisovich Volkov, ulits'a Koltsevaya, 169, kv. 6, all of Ufa, U.S.S1R.

Filed: Nov. 13, 1973 Appl. No.: 415,376

US. Cl. 431/168, 239/223 Int. Cl. F23d 11/04 Field of Search 431/168; 239/214.25, 223;

[ Jan. 28, 1975 3,175,600 3/1965 Powell 431/168 X 3,447,494 6/1969 Schwarz ct a1 431/168 X Primary Examiner-Edward G. Favors Attorney, Agent, or FirmWaters, Roditi Schwartz & Nissen [57] ABSTRACT An apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value comprises a housing accommodating a hollow shaft journalled in bearings and supporting a rotary atomizer at the end there of facing the combustion chamber, and an annular air duct for supplying air for combustion, which is arranged around the rotary atomizer. The hollow shaft accommodates a pipe for feeding the industrial wastes being burned to the inner surface of the rotary atomizer, as well as a pilot burner which is adapted to form an independently controlled flame along the axis of the spatter cone of the wastes being burned.

3 Claims, 2 Drawing Figures APPARATUS FOR ATOMIZATION AND COMBUSTION OF FLUID INDUSTRIAL WASTES HAVING LOW AND VARIABLE CALORIFIC VALUE The present invention relates to burner apparatus, and more particularly to apparatus for atomizing and combustion of fluid industrial wastes having low and variable calorific value, such as petroleum sludge.

The present invention may be the most advantageously used for thermal neutralization (by burning) of fluid or artificially fluidized industrial wastes having the calorific value both greater and lower than that at which self-sustained combustion is possible. The invention may be also used for combustion of various kinds of fuel containing water and contaminated with inorganic impurities.

The present invention may be the most efficiently used in those cases, where the volume of fuel having low calorific value to be burned or other economical considerations would require the employment of preheated air or the burning of the wastes in a combustion chamber under pressure, as well as in the case, where impurities in the form of readily volatile solvents or other products imparting the explosive properties to the mixture being burned are present in the wastes.

It is a long-felt need for oil-refining and petrochemical plants to solve the problem of the disposal of petroleum sludge formed during the purification processing in the equipment such as in tanks, slurry ponds and oil traps, sewage settling basins and the like. Such wastes comprise a non-stratificating mixture of dirty water and resinified oil products which form an emulsion with water and envelop solid impurities such as clay particles, scale, sand, oil coke grains and the like. The presence of even low-active detergents, such as waste alkali in this mixture additionally stabilizes it. The more pronounced are the colloid gel properties of such a mixture, the greater and more abnormal is the viscosity of the mixture, such mixture being difficult in batching and control. Even where constant volumetric or weight batching of such mixture of variable composition is available, it is difficult to ensure stable burning conditions, since it is very important for the combustion process to known the amount of the fuel component introduced into the combustion chamber per unit of time, the amount of air to be supplied, degree of combustion and other parameters being controlled on the basis of this amount. In order to ensure reliable ignition of such wastes, still another factor is important, namely the content of water in the mixture to be burned since water is evaporated at the very beginning of the combustion process so that a large amount of heat is consumed for that purpose just at the time, when the amount of heat released is still very small.

As a result, such wastes have a trend to spontaneous extinction and to absolutely unsatisfactory degree of combustion despite the fact that a total calorific value of wastes may be considerably greater than the lowest limit corresponding to self-sustained combustion.

In addition to such widespread wastes as petroleum sludge, the following wastes are obtained at chemical and petrochemical plants: waste alkalis, solutions containing carbon bisulphide, phenylic acids or chlorinated derivatives, wastes of biological purification plants, waste liquors containing cyan, toxic dyes and the like.

The most effective processing of all these wastes would be their thermal neutralization, that is, their combustion together with combustible wastes in a flame at a temperature of at least. l,00O-1,200C and at a predetermined degree of oxidation capacity of the medium.

Therefore, the admixture of such wastes to the main waste-petroleum sludge is undoubtedly effective, but this would additionallyincrease fluctuations of the calorific value of such mixture, that is its ignition capacity and the possibility of stablle combustion would become worse.

At present the problem of burning fluid industrial wastes is being solved at a number of plants by mixing this waste with a valuable fuel used a priori in an excessive amount, or by specifying a priori a lower yield of separation of an oil product from such mixture. This results in some fluidization of the mixture and ensures satisfactory ignition by using a burner; the combustion process control is not, however, achieved by these methods due to the fact that mechanical impurities are still present in the mixture being burned, as well as to non-uniform composition of the mixture, whereby it is necessary to add valuable fuel in a large excess; it is not possible to burn such mixture in jet or mechanical burners, and the formation of longer fuel spray is inevitable which is associated with the formation of soot, and hence carcinogenic products.

The most actual economical problem for industrial wastes having low and largely variable calorific value consists in the recovery of their combustion heat. The amount of such heat is rather large and it could reduce and in certain instances completely eliminate in the future the present unprofitableness of the combustion of such wastes, that is of the protection of natural water basins and atmosphere against contamination. Thus, about 3-5 tons of steam per hour can be obtained by burning petroleum sludge at an average-size oil processing plant even with rather incomplete recovery of heat. Where valuable fuel is admixed to the mixture being burned (waste) in order to incinerate absolutely incombustible wastes, the degree of heat recovery will be still more increased due to this additional fuel. However, the variable content of the fuel component in such mixture, and hence the difficulties arising in the solution of the first problem reliable burning and complete combustion and the use of conventional automatic control systems which are unsuitable for such viscous liquid (waste) contaminated with mechanical impruities, does not enable the control of heat released during the combustion. Moreover, in such waste-heat boilers even constant steam pressure cannot be maintained in many cases (without additional expenses).

Therefore, it is unsatisfactory and extremely inflexible control of the combustion process in burning wastes having low calorific value, which is the worse, the more complete is the degree of extraction of valid components, such as an oil product, that hampered until now normal recovery of heat and made of the protection of the environment against such wastes completely unprofitable buisness.

Known in the art is an apparatus for atomization and combustion of finely ground coal which is fluidized with water so as to obtain a pumpable suspension. This apparatus comprises a rotary burner including a housing having bearings and accommodating a hollow rotary shaft rotated through a V-belt transmission by an electric motor, a bowl-shaped rotary atomizer being supported on the shaft end facing the combustion chamber. Mounted in the shaft is a pipe adapted to feed the coal-water suspension to be burned to the inner surface of the rotary atomizer. In order to utilize hot air during the combustion of the water-coal suspension, a watebcooled screen is arranged around the shaft bearings. A converging conical annular section passage for feeding hot air for combustion terminates at the outlet or atomizing edge of the rotary atomizer, an adjusting annular shutter being mounted at the output of the passage.

The viscosity of water-coal suspension to be burned in this apparatus is largely variable depending upon the content of water, and generally it is rather high; where too excessive amount of water is used, the difficulties may be encountered in igniting, and spontaneous extinction of flame may also take place. However, as the suspension is specially prepared for that purpose, the arrangement of a device for preparing this suspension the most close possible to the burner will permit to substantially eliminate the possibility of very large variations of its composition. Therefore, the burner would practically operate with a mixture having a calorific value of about 4.5-5 thousand kcal/kg which allows for volumetric or weight batching.

As is known, an ideally atomized mixture of the medium petroleum sludge type mixed with an amount of air which is theoretically required for combustion, has the lower theoretical limit of the calorific value allowing self-sustained combustion (about 1.9-2.0 thousand kcal/kg with unheated air and about 1.5-1.6 thousand kcal/kg with air heated at 200C). However, under the actual conditions, the coarser are the particles of the mixture being burned and the less intimately they are mixed with air so that they require a greater air excess ratio, the greater is the actual lower limit of the calorific value and the farther this limit is shifted from the theoretical one. This situation becomes worse (the space between the actual and theoretical limits becomes greater), where the combustion is performed in a combustion chamber having elevated heat losses, or a chamber, which is screened even partially, so that for conventional waste-heat boilers provided with ordinary burners this lower limit ranges from 3 to 4 thousand kcal per kg of a mixture of combustible and uncombustible components being burned.

Therefore, this known apparatus cannot ensure the reliable atomization and complete combustion of a large variety of industrial wastes of the type of petroleum sludge.

In addition, this apparatus is not unsuitable for peculiar conditions of operation with liquids capable of releasing explosion hazardous vapours, as well as for operation in the combustion chambers under elevated pressure despite the presence of two stuffing-box seals mounted between the hollow shaft and the rotatable parts located inside and outside thereof.

Since this burner is provided with the protective water-cooled screens only outside the bearings and has no protection against heat transmitted through the short and thick shaft to the bearing, which the nearest one to the rotary injector, it either will have heavy limitations as to the admissible air heating temperature, or will be unreliable in operation. Furthermore, the water-cooled screens around the bearings made in the form of a helically wound coil, which are to a certain extent suitable for a rotary burner, will become absolutely unsuitable, where it is required to provide a simple and inexpensive unit for combustion of fluid wastes without the investments for erection of a building or shed.

Such water-cooled screens, if used without a complicated supply system for chemically purified water, will constitute themselves the source of troubles.

It is an object of the present invention to provide an apparatus which ensure reliable atomization and the most effective combustion of fluid industrial-wastes having low and variable calorific value with any fluctuations of the composition thereof, including those resulting in the reduction of the calorific value below the lowest limit of self-sustained combustion.

It is another object of the invention to provide an apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value which is controlled in such a manner that the amount of heat released in the apparatus could be either maintained constant, or positively controlled independently of fluctuations of the calorific value of the waste being burned. The apparatus should be controllable by means of a simple automatic control system which operates independently of the degree of contamination of the industrial waste with mechanical impurities and its viscosity. Only with such controlled apparatus the accomplishment of the first object reliable atomization and effective combustion can be practically used, and the apparatus can become suitable for installation in the combustion chamber of a waste-heat boiler or in the combustion chamber of a technological furnace, wherein uncontrolled heat inflow due to accidental fluctuations of the composition of the mixture being burned, clogging of the control valve and the like is absolutely inadmissible.

Still another object of the invention consists in more simple structure of the apparatus and elimination of emergency situations at any degree of air heating, or on the contrary at any frost during the winter, as well as under boosting of the combustion chamber and transition for operation under elevated pressure.

With these and other objects in view, the invention consists in the provision of an apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value, comprising a hollow shaftjournalled in a housing by means of bearings, a rotary atomizer supported at the end of this shaft facing a combustion chamber, a pipe accommodated in this shaft and adapted to feed the fluid industrial wastes being burned to the inner surface of the rotary atomizer, and an annular air duct arranged around the rotary atomizer and adapted to supply air for combustion, wherein according to the invention mounted in the hollow shaft is a pilot burner which is adapted to form an independently controlled flame along the axis of the spatter cone of the wastes being burned.

Such additional and controlled flame inside the very beginning of the spatter cone of the waste being burned formed by means of the pilot burner arranged coaxially with the apparatus, imparts the following new properties to the rotary burner as a whole: a thermal impact is obtained at the very beginning of the spatter cone, and considerably greater fraction of drops of the waste being atomized, and which is important, ofthe finest drops which move closer to the spatter cone axis will get into the pilot flame. These fine drops are rapidly heated, evaporate their water, and after they have been ignited and changed their path under the action of almost radially flowing gases from the pilot burner they turn away from the axis and get mixed with the remaining mass of drops of the spatter cone. As a result, the main mass of the spatter cone is ignited not only by using valuable fuel burned in the pilot burner, but also by means of the ignited fine drops of the waste itself. All these phenomena take place at the very beginning of and inside the spatter cone, whereby the effect of the burning of small amounts of valuable fuel is multiplied.

In addition, the independent control of the additional flame permits to consume valuable fuel only then, when it is necessary to increase insufficient ignition capacity of the mixture.

According to the invention the pilot burner and the pipe for feeding the fluid industrial wastes being burned is preferably closed by means of a fixed casing accommodated in the hollow shaft, the air for the pilot burner being supplied through this casing.

Such an assembly casing, together with its outer bracket, considerably simplifies the assembly and disassembly of the pilot burner, as well as the cleaning and replacement thereof.

According to the invention this fixed casingis preferably accommodated in the hollow shaft in such a manner as to define an annular space therebetween, the space being closed on the side opposite to the rotary atomizer by means ofa labyrinth seal and communicating with a source of cooling air which supplies air for combustion. This embodiment of the apparatus permits to make the only seal of the apparatus more simple and contactless, while concurrently solving the problem of the continuous blusting of the internal cavities of the apparatus with compressed air, whereby the accumulation of explosion hazardous vapours therein is eliminated; at the same time there is provided continuous expulsion of the combustion gases which could otherwise penetrate into the spaces and internal cavities of the burner upon accidental pressure increase in the combustion chamber, the expulsion being effected with air under pressure, which is somewhat greater than that in the combustion chamber. This permits to use such an apparatus both for operation with air for combustion heated at 250-300C and for operation in the combustion chambers under elevated pressure generally resulting in a great saving of the investments in the combustion unit as a whole, as well as in considerably simplification of its structure. In addition such continuous blusting of the hollow shaft with a moderate cool air flow is effected in counter-current (in the direction opposite to the heat flow along the shaft) and ensures the efficient cooling thereof.

According to the invention the hollow shaft is preferably provided with at least one passage for feeding cooling air from the annular space into the housing for washing the bearing from either side.

This embodiment of the apparatus permits to ensure the cooling of the bearings from either side in addition to the cooling of the hollow shaft itself journalled in these bearings, and two years of continuous operation of such apparatus have shown that such an embodiment actually guaranteed very long trouble free service life. This cooling system operates without failures during the entire period of the operation of the apparatus, it is very simple and does not require any maintenance,

the system being automatically put on and off upon the energization and stoppage of the apparatus.

Other objects and advantages of the invention will become more apparent from the following description of a specific embodiment thereof illustrated in the accompanying drawings, in which:

FIG. 1 schematically shows a longitudinal section of an apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value according to the invention;

FIG. 2 is a cross sectional view taken along the line II in FIG. 1.

The apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value comprises a hollow shaft 1 journalled in a housing 2 in bearings 3 and 4. The shaft 1 is rotated through a pulley 5 and a V-belt transmission 6 by an electric motor 7. Mounted in the hollow shaft 1 is a pipe 8 for feeding the waste being burned to the inner surface of a bowl-shaped rotary atomizer 9 which is mounted at the end of the shaft 1 facing a combustion chamber. A

conically converging annular air duct 10 supplying air for combustion to the edge of the rotary atomizer 9 is arranged around the housing 2 of the rotary atomizer 9.

A pilot burner 11 is mounted in the hollow shaft 1 ad jacent to the pipe 8 for feeding the waste to be burned, the pilot burner being supplied with valuable fuel through a socket pipe 12 and provided with a pneumatic actuator 13 which acts upon a long obturating needle 14 extending inside the burner up to its injection nozzle 15.

As shown in FIGS. 1 and 2, the pilot burner 11 and the pipe 8 for feeding the waste being burned are enclosed in a casing 16 accommodated in the hollow shaft 1 and fixed to a bracket 17. Air for combustion is fed into the burner 11 through a socket pipe 18 connected to the casing 16 so as to supply with air the nozzle 15 of the pilot burner 11.

A space is provided between the rotary shaft 1 and the fixed casing 16 which is closed on the side opposite to the rotary atomizer by means of'a simple contactless labyrinth seal 19, the fixed part of the seal being provided with a socket pipe 20 for feeding cooling and expelling air into said space. A plurality of passages 21 are provided in the wall of the hollow shaft 1 for passing the cooling and expelling air fed from the socket pipe 20 into the interior of the housing 2 to the bearings 3 and 4.

The apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value according to the invention operates as follows:

Fluid industrial waste having low calorific value, which is to be burned, is fed along the arrow A" in the pipe 8 mounted in the hollow shaft 1, wherefrom the waste being burned flows to the inner surface of the rotary atomizer 9. All passages for the waste being burned are designed to pass therethrough solid materials (of a size up to 6 mm) so as to simplify, and in some cases to eliminate even the check filtering of the waste being burned.

The electric motor 7 rotates at a high speed the hollow shaft 1 through the V-belt transmission 6 and the pulley 5 so as to rotate the bowl-shaped rotary atomizer 9 mounted at the end thereof facing the combustion chamber. The waste being burned, which gets splashed upon the inner surface of the atomizer is distributed thereover in the form of substantially thin and uniform film due the action of centrifugal forces and moves towards the outer edge of the atomizer 9. Upon separating from this edge the thin film of the fluid waste being burned is strongly stretched so as to become thinner and is exploded into fine drops upon hitting against the air stream. Air for combustion, against which the waste being atomized is hit, is supplied by means of a blower through an air heater (not shown in the drawings) as indi'catedby the arrow B into the annular air duct 10 and further to the edge of the rotary atomizer 9. In order to ensure high degree of combustion of the fluid industrial wastes having low and largely variable calorific value in the rotary burner, including the cases, where their calorific value is about equal to the theoretical lowest limit of self-sustained combustion, as well as to enable the complete combustion of mixtures which are not capable of self-sustained combustion at all, according to the invention mounted in the hollow shaft 1 is the pilot burner ll adapted to create an independently controlled flame along the axis of the spatter cone of the industrial wastes being burned.

FIG. I shows the considerable changes in the ignition conditions due to the use of the pilot burner, wherein the pathes of drops are traced, which are formed due to the atomization of the waste being burned. All the drops begin their movement under the action of centrifugal forces in the radial direction, but when they begin to be deflected under the action of air fed for combustion, the finer being these drops, the more abrupt is the change of their path, that is the phenomenon of aerodynamic separation of the drops by the size takes place.

In FIG. 1 the path of the finest drops is indicated at C and shown with dotted line, the path D for medium-size drops is shown with dash line, and the path E of larger drops is shown with elongated-dash line. As shown, the finest drops are the most abruptly deflected from their original radial path and move directly adjacent to the longitudinal axis of the spatter cone. It is obvious that it is very easy to ignite the finest drops, whereby the formation of the pilot flampe in the spatter cone (in FIG. 1 the path of the hot gases from the pilot burner is shown with long arrows F) enables the achievement of the desired result with considerably low consumption of valuable fuel.

But this does not exhaust all the advantages: as shown in FIG. 1 the pilot burner II mounted according to the invention forms the pilot flame at the very beginning of the spatter cone, that is just at the point, where an additional heat for predrying and ignition is the most necessary for the waste having a low calorific value and containing water. The second deflection of the path C (the path of the finest drops), which is now directed somewhat outside away from the axis (FIG. 1), corresponds to the impingement of the drops against the hot gases from the pilot burner 11.

Therefore, the pilot burner 11 mounted according to the invention, which uses the phenomenon of aerodynamic separation of the drops so as to first ignite the finest among them at the very beginning of the spatter cone, will throw away the ignited fine drops towards the main mass of the atomized waste, whereby the ignitingaction of a small pilot flame of the burner 11 is improved and multiplied due to this phenomenon. The 2 year operation experience has shown that by using by several times smaller amount of valuable fuel than usually, lowgrade wastes and even the worst fluid wastes having the lowest possible calorific value can be burned, and as to ensure the efficient combustion the entire length of the spatter cone was used, a shorter fuel spray was obtained so that in burning e.g. 3-3.5 tons per hour of a waste having a calorific value corresponding to the lowest limit of self-sustained combustion the spray was no longer than 2.6-3.0 m, and even with moderate dimensions of the combustion chamber satisfactory degree of combustion is obtained.

Stable and the most effective operation of the apparatus according to the invention with its inspection by the operator at regular intervals only l'2 times during the shift in burning any wastes having low calorific value, including those, which are not capable of selfsustained combustion, is achieved due to the fact that the pilot burner 11 is independently controlled from a thermocouple sensing the temperature of the exhaust fuel gas (not shown in the drawings). Where this temperature will drop below a predetermined level, such as below l,200C, which guarantees satisfactory degree of combustion, the pneumatic actuator 13 will displace the obturating needle 14 according to the isodromic law so as to partially open the nozzle 15 of the pilot burner 11.

This will result in an increased additional heat to be supplied into the spatter cone to such an extent as to restore the dynamic equilibrium between the inflow and outflow of heat in the combustion chamber at the level of a predetermined temperature, e.g. l,200C independently of the fact that at that moment the calorific value of the waste being burned has diminished. At

the end of such a period of reduced calorific value of the waste being burned (for instant, where a batch of a very poor mixture fed into the pipe 9 has been processed, or upon the completion of the refinery operations in the equipment producing the component of the waste having the lowest calorific value), the temperature in the combustion chamber will begin to grow, and the pneumatic actuator 13 will obturate the nozzle 15 by the needle 14.

The apparatus incorporates the following possible modes of operation:

a mixture fed for combustion has a margin of the calorific value only at some time intervals, for instance due to a simple system of collection and homogenization of the composition of wastes, and its calorific value is reduced to the theoretically lowest limit and even below it. The pilot burner should be adjusted for a constant supply of valuable fuel in an amount of 6-9 kg/h and should be connected to the automatic control system so as to be ready at any moment for a sudden change either for a batch of waste with elevated water content, or a batch of waste from the bottom portion of a tank containing excessive amount of mechanical impurities, etc. Only with such on duty" operation of the pilot burner 11 the apparatus will be capable of automatically ensuring an instant and trouble-free control over any large range of changes;

a mixture of wastes is fed for burning, which is so completely separated from fuel components that its average calorific value is constantly below the lowest limit of self-sustained combustion.

In this case the same automatic control system of the pilot burner 11 will maintain a predetermined temperature in the combustion chamber, e.g. l,200C, independently of fluctuations of the composition of the waste mixture, whereby the combustion of the waste is ensured with a short spray and satisfactory degree of combustion with the greatest possible effectiveness which is only by -7 percent worse than that theoretically possible;

a mixture of wastes fed for burning, such as waste alkali, phenolic acid water or water from biological purification plants and the like, has absolutely negligeable, almost zero calorific value which is much more less than all possible limits. In operating in the automatic mode, the apparatus ensures rather effective incinera-- tion of such a mixture with the valuable fuel consumption which is considerably lower than in the case, where these wastes would be emulsified with the valuable fuel and then burned in the known burners. In this case the amount of heat required for incineration is supplied to the combustion chamber mainly due to the supply of valuable fuel through the pilot burner 11.

In order to simplify the replacement, as well as to facilitate the cleaning, repair and adjustment of the pilot burner, and if necessary to enable the cleaning of the pipe 8 feeding the waste being burned to the inner surface of the rotary atomizer 9, the pilot burner 11 and the pipe 8 feeding the fluid wastes being burned according to the invention are enclosed in a fixed casing 16 accommodated in the hollow shaft 1, the primary air for the pilot burner It being fed through this casing.

This fixed casing 16 is accommodated in the hollow shaft 1 with the formation of an annular space preventing the shaft 1 from interfering with the casing 16, and according to the invention this space is closed on the side opposite to the combustion chamber by means of the simple contactless labyrinth seal 19. Therefore, it is sufficient to unbolt the bracket 17 so that the casing 16 could be withdrawn together with the pilot burner 11 and the pipe 8 for feeding the waste being burned mounted therein since these parts will obviously require the most frequent cleaning, adjustment and other maintenance operations as compared to other parts of the apparatus.

During the operation of the rotary atomizer 9, in particular in the case, where air for combustion is fed heated at 150-250C so as to reduce the theoretically lowest limit of the calorific value at which the combustion of a given type of waste is still possible without consuming valuable fuel, it is necessary, first, to takeoff heat from the bearings 3 and 4 and the hollow shaft 1, second, to prevent even accidental and short-time penetration of the hot combustion gases into the spaces and cavities of the rotary atomizer, and third, to blust all empty cavities in the rotary atomizer so as to prevent explosion hazardous vapours from accumulating therein. For that purpose, the annular space between the inner surface of the hollow shaft 1 and the outer surface of the fixed casing 16 is closed on the side opposite to the rotary atomizer by means of the labyrinth seal 19, and according to the invention communicates with the source of cooling air, e.g. with the output of the blower supplying air for combustion, while the hollow shaft I itself is provided with at least one passage 21 for passing therethrough the cooling air from the annular space into the housing 2 for cooling the bearings 3 and 4 from either side.

This flow of the cooling and expelling air ensures, first, the efficient counter-current cooling of the hollow shaft 1 (the cooling air flows in counter-current with the heat flow from the combustion chamber), second, the cooling of the bearing 4 from either side, this bearing being the most critical due to the danger of the melting out of the lubricant, and third, the blusting and expulsion in all spaces and cavities of the rotary atomizer, which becomes suitable for operation not only with accidental pressure increase in the combustion chamber, but also for continuous operation in the combustion chamber under elevated pressure.

It will be apparent from the above description that the apparatus for atomization and combustion of fluid industrial wastes having low and variable calorific value according to the invention is completely suitable for use in the combustion chamber of a waste-heat boiler or in the combustion chamber of a technological furnace and is capable of effectively burning any fluid industrial wastes having low and variable calorific value, including the cases, where this calorific value becomes even lower than the theoretically lowest limit of selfsustained combustion. Due to this structural suitability of the apparatus the latter permits to considerably simplify the system of collection and homogenization of composition of the wastes being burned and to operate practically without any supervision.

What is claimed is:

I I. An apparatus for atomizing and combustion of fluid industrial wastes having low and variable calorific value, comprising: a housing; a hollow shaft accommodated in said housing; a combustion chamber; a rotary atomizer mounted at the end of said hollow shaft facing said combustion chamber; a fixed casing located within said hollow shaft for supplying air to a burner which is arranged within said casing and is intended to form an independently controlled flame along the axis of a spatter cone of the wastes being burned; a pipe arranged within said fixed casing for feeding fluid industrial wastes being burned to the inner surface of said rotary atomizer; bearings mounted in said housing to carry said hollow shaft; and an annular air duct arranged around said rotary atomizer for supplying air for combustion.

2. An apparatus as claimed in claim I, said fixed casing being positioned in said hollow shaft with an annular space therebetween for preventing said shaft from interfering with said casing; said space being closed on the side opposite to said rotary atomizer by means of a labyrinth seal and communicating with a source of cooling air which supplies air for combustion.

3. An apparatus as claimed in claim I, said hollow shaft being provided with at least one passage for passing cooling air therethrough from said annular space into said housing for cooling said bearings from either side. 

1. An apparatus for atomizing and combustion of fluid industrial wastes having low and variable calorific value, comprising: a housing; a hollow shaft accommodated in said housing; a combustion chamber; a rotary atomizer mounted at the end of said hollow shaft facing said combustion chamber; a fixed casing located within said hollow shaft for supplying air to a burner which is arranged within said casing and is intended to form an independently controlled flame along the axis of a spatter cone of the wastes being burned; a pipe arranged within said fixed casing for feeding fluid industrial wastes being burned to the inner surface of said rotary atomizer; bearings mounted in said housing to carry said hollow shaft; and an annular air duct arranged around said rotary atomizer for supplying air for combustion.
 2. An apparatus as claimed in claim 1, said fixed casing being positioned in said hollow shaft with an annular space therebetween for preventing said shaft from interfering with said casing; said space being closed on the side opposite to said rotary atomizer by means of a labyrinth seal and communicating with a source of cooling air which supplies air for combustion.
 3. An apparatus as claimed in claim 1, said hollow shaft being provided with at least one passage for passing cooling air therethrough from said annular space into said housing for cooling said bearings from either side. 